The present invention relates to the field of vegetation cutting quality, disposal of cutting remains, productivity and ergonomics. While it also applies to conventional symmetrical flexible line, additional significant benefits are more particularly directed to the application of aerodynamic cutting line features in combination with the flexible line trimmer and a wheeled attachment apparatus that easily connects to the trimmer shaft. These inventions allow the evolution of a whole new series of maneuvering options and tools with universal and multi-task capabilities.
Heretofore, there have been many cutting methods and devices for the cutting, edging, mulching, blowing and sweeping, vacuuming, and disposal of the grass, weeds, leaves, and other types of vegetation involving well-manicured lawns, walkways, golf courses, cemeteries, industrial establishments, roadways, drainage areas, waterways, lake and stream edges, all of which are associated with obstacles such as embankments, generally uneven surfaces, steep slopes, trees, rocks, posts, building edges, fence lines, edges of walkways, flower and shrubbery beds, and a whole variety of other type impediments.
Such work functions are extensively applied to a wide variety of establishments such as small plot home sites, large estates, industrial and business centers, townships, parks, cemeteries, golf courses, local, state and federal highways, waterways, etc. all of which have experienced increased demands for high quality manicuring and cosmetics. This demand has evolved more extensively in the United States and is growing in the remaining areas of the world, principally due to the evolution of more productive and specialized equipment as well as the horticultural knowledge boom, all of which has been provided at a reasonable cost. Thus, there has been the creation of a value-achieved and affordable benefit. Accordingly, huge markets have developed for a wide variety of rotary mowers (riders, walk-behinds), hovering mowers (rotary mowers without wheels), edgers, blowers (hand-held and back-supported), flexible line trimmers and brush cutters, hedge trimmers, cultivators, and other specialty tools such as thatchers, aerators, shredders, leaf mulchers, vacuums, etc. to perform such a wide variety of different and necessary operations to achieve all these advancing cosmetic and demanded high quality standards. Each tool provides generally specific and functional specialty segments of an overall process. Such tools also require unique skills to operate, know how, specialty repair and maintenance tools, storage space, transporting such tools to the work location as well as the need to switch from one tool to another.
Development progress within each specialty tool has been impressive as existing tool design has been refined, however, these tools have not been without problems in one way or another in that they are laborious and time consuming to use, have their own safety concerns, are complex and heavy, are difficult to maneuver and transport, require substantial space to store, and are largely inefficient and noisy both within the environment and to the operator. This is largely due to the multitude of specific work requirements within the extensive and total process of vegetation cutting and maintenance as tools have become very specialized and accordingly designed to perform specialized and seasonal tasks. Examples of such tasks are mowing grass; edging or cutting cleanly along walkways and flowerbeds; trimming into steep terrains, up to trees, and edging along buildings, walkways, and fences; using brush cutter metal blades to cut heavy vines and weeds; blowing or sweeping cuttings and debris off walkways; collecting grass clippings and debris; mulching and collection of fallen leaves; and residual or interactive steps required to interchange tools, transporting them, maintaining them, and finally storing them for future use.
The more popular rotary blade, wheel supported mowing process utilizes a protected rigid steel blade that runs at uniform and low tip speeds of 15000-18000 feet per minute while requiring strong protective decks and discharge chutes, one-way wheel travel, and protected operator work zones, i.e. at the rear of a walk-behind or seated on a riding mower. Since injuries involving the clearing of grass clogging from a discharge chute are a major concern, complex blade stopping systems are required but are a nuisance or are frequently bypassed by users. Further, such mowers are not able to safely cut beyond obstacles, steep slopes, swails, or confined locations. Some of the more expensive mowers incorporate a zero turning radius but cannot move sideways. Specialty hovering mowers move in all lateral directions and do not use wheels but require added power to create an air cushion, and must utilize flexible cutting line to prevent operator foot injuries from side to side motions.
The rotary mower cutting process also requires added power to pump airflow so as to lift grass for clean cutting and then to accelerate cuttings through special discharge chutes and extensions designed and placed accordingly to reduce clogging and thrown objects. Adding these necessary features and components sacrifices versatility and maneuverability. Further, these mowers cannot cut along or up to obstacles due to the interference from their required blade protecting deck and related discharge chute extensions.
To assist in other processes where rotary mowers cannot safely function, the operator hand-held flexible line trimmer, a relatively recent product of the 70's, has become a very important and welcomed tool to trim, edge and cut grass over and around and into tight places. This versatile tool allows the operator to move the trimmer head to any location or position and to trim horizontally, vertically, or at head angles in between. The trimmer filled a much-needed void but also is not without its own inherent problems. The flexible fishing line utilized for the grass trimmer which is made from an extrusion process into various symmetrical shapes (round, square, star, triangular, etc.), is overstressed, easily breaks, and requires complex replacement mechanisms to replenish the cutting length and/or with more frequent use of manual replacement systems. This conventional line requires high speed to reach an effective centrifugal stiffness while it creates a high pitch noise. Attempts to use heavier and larger diameter line sizes add to the already high and wasted power required to overcome air drag as well as higher noise. Further, speed drops with the thicker line sizes, clutches burn out, and cutting quality diminishes further from conventional cutting lines that normally produce a mashing type cut. The blunt surface of the line does not cut or sever grass but mashes it while pushing it downward and away from the cutting plane. As a result, grass browning (mashed grass dries out-browns at the tip) results while unevenness of cutting height remains a major problem and accordingly a reduction in manicuring quality.
Many unsuccessful attempts were historically ventured with wheeled apparatus to convert the flexible line trimmer to a mower. High wheel trimmers with only a fixed horizontal plane of cut, have limited versatility with many disadvantages similar and representative of the rotary mower. Conventional high wheel trimmers do not allow the head to tilt for edging and other trimming positions, and like hand-held grass trimmers suffer from overstressed or weak line breakage and replenishment problems which dramatically increase user frustrations. Additionally, flexible line trimmers require high tip speeds (25000-32000 feet per minute), because they rely on centrifugal force applied to a relatively low mass to create a transfer strength of torque and power into the cutting process (centrifugal stiffness). When the fast moving line hits an obstacle like a fence or small piece of brush, the line continues to move and wraps around the obstacle, self-locking it only to ultimately break off. Additionally, the small cross-sectional area of the line wears rapidly on abrasive surfaces, further creating repeated loss of its cutting length. Additionally, these lines split on the ends known as fibulation due to high impact. At lower speeds and into more resistant vegetation, the flexible symmetrical line easily folds and/or slides off the material it intends to cut, thus creating great limitations in cutting more sizeable vegetation. Accordingly, flail systems (plastic blades on hinge pin), which often shatter and break, and metal blades are necessary to cut heavy weeds, vines or thick/strong vegetation. The flex line trimmer then converts to a metal blade tool known as a “brush cutter”. Similarly, a specialized vertical metal blade tool (“stick blade edger”) is often chosen to cut grass and sod evenly and close to walkways because the flexible line is too weak and very difficult to control under such operations.
Additionally, longer use of a handheld flexible line trimmer is laborious and becomes tiring and fatiguing. The process also creates gouging or scalping into grass along walkways and sloping contours as the operator attempts to mow evenly with the trimmer into these areas. The strenuous process is further compounded because the trimmer's weight is extended or cantilevered from the operator's body when added reach is further needed. This leads to physical back strain especially to elderly people or to those with preexisting back ailments. A harness strap is infrequently used to more evenly suspend the weight down through operator's torso but also creates restriction to more needed operator reach and need for head tilt control for specialized trimming and cutting. It is also very difficult to hold and control the invisible cutting plane of conventional line to a level position when walking or moving with the trimmer, thus creating poor quality, and unsightly gouging, and scalping.
The removal of unwanted clippings and debris is another important part of the overall process that requires the use of higher energy consuming, and generally noisy handheld or backpack blowers. Again, the operator must transport and interchange to another tool, a centrifugal blower, which uses an inherently noisy compression and expansion cycle to produce high velocity air directed through an output nozzle to blow away clippings and debris from prior processes. Community environmental noise and dust has been of great concern creating local ordinances and forbidden use of such products in some areas of the United States.
Additionally, the greater proportion of these uniquely different and selective handheld tools are powered by two cycle engines and subject to severe emission regulations. Lower emission alternatives, such as the heavier and less powerful four cycle engines or two cycle engine catalytic converters will only add weight and present more complexities when powering these commonly used rotary mowers, flexible line trimmers, brush cutters, edgers, and blowers. Electric motors which offer environmental benefits, AC or cordless DC, are currently limited due to cumbersome cords or the burdens added by battery weight with shortened operating power capacity and duration.